troubleshooting a Dell Dimension 8100 PC that will not boot

Troubleshooting a Dell™ Dimension™ 8100 PC that will not boot.

Symptoms. Plugging in the power cord, the green power light comes on, the CD light briefly goes green, nothing appears on the screen. Further investigation reveals that the case/CPU fan runs, power supply fan runs, the hard disk briefly spins. On the back of the case are 4 lettered lights: ABCD. A & B are yellow, C & D are green. Opening the case, on the system board there are 2 lit lights. An amber one in the lower right area labeled “STANDBY LED”, and a green one by the memory labeled “STR”.

A search engine search reveals others have had similar problems, some forum threads:

Some people have fixed their 8100s but some have not not.

The good news is this PC is built well, like an old Buick, and has good online documentation.

The bad news is this PC is dated, uses proprietary parts like the power supply, and used RIMM memory.

Troubleshooting in progress. Click for a larger picture. Note the 4 diagnostic lights just under the keyboard and mouse connections, the 2 RIMM memory modules on the table and the swing up power supply (!).

Some of the troubleshooting I did:

The diagnostic lights on the back ABCD. A & B are yellow, C & D are green, the documentation says the definition is “Memory failed to be sized or enabled.” and the corrective action is to reseat the RIMMs. Tried removing, and reinstalling the 4 256MB RIMMs in pairs, different combos. Clean slots and RIMMs. I don’t have any RIMMs to substitute (RIMM tech was not popular). RIMMs must be populated from the slots nearest the CPU and in pairs. Illegal combos produced beep error codes, ie 5-2-2-1.

Since there is no video, I tried a different AGP card and a PCI video card.

Also tried other troubleshooting techniques like

  • unplugging the hard disk, DVD.
  • removing the only other card, the sound card.
  • reseating all motherboard-device cables.
  • changing the CMOS battery.

Can’t try swapping the power supply because of the Dell proprietary connector. Can’t try swapping the CPU or system board because I don’t have these replacements.

At this point I suspect the power supply, system board or CPU.

(The repair history includes: replaced hard disk, replaced CMOS battery, replaced sound card, replaced case/CPU fan.)

My recommendation is scrap the PC. The Dell part(s) and labor to fix this PC will likely be expensive and the system is old and liable to fail again. The system is a 1.7GHz/1GB RAM PC.

Happy troubleshooting!

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